Synovial calprotectin is a reliable biomarker for periprosthetic joint infections in acute-phase inflammation - a prospective cohort study.

PURPOSE: Diagnosing periprosthetic joint infections (PJI) are challenging and may be hampered by the presence of other causes of local inflammation. Conventional synovial and serum markers are not reliable under these circumstances. Synovial calprotectin has been recently shown as a promising biomarker for PJI in total hip (THA) and total knee arthroplasty (TKA). The aim of this study is to investigate if calprotectin is reliable for PJI diagnosis in cases with accompanying inflammation due to recent surgery, dislocation or implant breakage in primary and revision TKA and THA. METHODS: Thirty-three patients were included in this prospective study between July 2019 and October 2021 (17 patients undergoing surgery < 9 months, 11 dislocations, five implant breakage, respectively). Synovial white blood cell count (WBC), percentage of polymorphonuclear neutrophils (PMC), serum C-reactive protein (CRP) and synovial calprotectin, using a lateral-flow-assay, were analysed. These parameters were tested against a modified European-Bone-and-Joint-Infection-Society (EBJIS) definition with adjusted thresholds to account for the local inflammation. Statistic quality criteria were calculated and compared using a binary classification test. RESULTS: Seventeen patients were classified as confirmed infections according to the modified EBJIS definition (13 THA and 4 TKA). The calprotectin assay yielded a sensitivity of 0.88 (0.64, 0.99), a specificity of 0.81 (0.54, 0.96), a positive predictive value (PPV) of 0.83 (0.59, 0.96) and a negative predictive value (NPV) of 0.87 (0.60, 0.98). CONCLUSIONS: Even in the presence of local inflammation due to other, non-infectious causes, calprotectin is a reliable diagnostic parameter for the detection of a PJI in primary and revision THA and TKA.

[Extended access to revision knee replacement : Intraoperative possibilities for improved joint exposure in complex knee arthroplasty procedures]. / Erweiterte Zugänge zum Kniegelenk in der Revision : Intraoperative Möglichkeiten zur verbesserten Gelenkexposition bei komplexen Eingriffen in der Knieendoprothetik.

In most cases, a standard access via a medial parapatellar arthrotomy with a carefully performed release technique is sufficient for a good exposure of the knee joint in the revision situation. Crucial steps are targeted scar removal, sufficient soft tissue release and recreation of the shifting layers. Tuberosity osteotomy is an effective option for extended exposure at the distal joint region, facilitating a patella replacement to correct abnormalities in the patellofemoral joint. Extended exposure to the proximal joint is possible with the rectus snip and the VY plasty technique. Due to the rather poor results, a quadriceps turndown should be seen more historically and should no longer be used. In extreme cases, a femoral peel or an osteotomy of the medial epicondyle can help achieve the reconstruction of a joint. The latter techniques are reserved for selected cases and always require a linked implant.

C-Reactive Protein Pretreatment-Level Evaluation with Histopathological Correlation for Chondrosarcoma Prognosis Assessment-A 15-Year Retrospective Single-Center Study.

BACKGROUND: An aberrant cellular microenvironment characterized by pathological cells or inflammation represents an added risk factor across various cancer types. While the significance of chronic inflammation in the development of most diffuse tumors has been extensively studied, an exception to this analysis exists in the context of chondrosarcomas. Chondrosarcomas account for 20-30% of all bone sarcomas, with an estimated global incidence of 1 in 100,000. The average age at diagnosis is 50, and over 70% of patients are over 40. This retrospective study aimed to examine the role of C-reactive protein (CRP) as a prognostic factor in relation to the histopathological findings in chondrosarcoma. METHODS: In this retrospective study, 70 patients diagnosed with chondrosarcoma and treated between 2004 and 2019 were included. Preoperative CRP levels were measured in mg/dL, with non-pathological values defined as below 0.5 mg/dL. Disease-free survival time was calculated from the initial diagnosis to events such as local recurrence or metastasis. Follow-up status was categorized as death from disease, no evidence of disease, or alive with disease. Patients were excluded if they had insufficient laboratory values, missing follow-up information, or incomplete histopathological reports. RESULTS: The calculated risk estimation of a reduced follow-up time was 2.25 timed higher in the patients with a CRP level >0.5 mg/dL (HR 2.25 and 95% CI 1.13-4.45) and 3 times higher in patients with a tumor size > pT2 (HR 3 and 95% CI 1.59-5.92). We can easily confirm that risk factors for reduced prognosis lie in chondrosarcoma high grading, preoperative pathological CRP- level, and a size > 8 cm. CONCLUSIONS: A pretreatment CRP value greater than 0.5 mg/dL can be considered a sensitive prognostic and risk factor for distant metastasis for chondrosarcoma patients.

Importance of Hip-Spine Syndrome in Hip Arthroplasty: Influence on the Outcome and Therapeutic Consequences. / Der Stellenwert des Hip-Spine-Syndroms in der Hüftendoprothetik: Einfluss auf den Behandlungserfolg und therapeutische Konsequenzen.

Correct interaction between the spine, pelvis, and hip is an essential condition for successful progress after total hip replacement. Spinal pathologies, such as degeneration, fractures, and spinopelvic imbalance with and without lumbar fusions, are closely associated with an increased risk of impingement or even dislocation of the prosthesis. To significantly reduce this risk, various parameters are required to quantify the risk groups. Knowledge on the presence of stiffness of the spine (change in pelvic tilt between standing and sitting at < 10°) and sagittal spinal deformity (pelvic incidence-lumbar lordosis mismatch > 10° or 20°) is essential in identifying patients with corresponding risk. The individual risk profile can be assessed through a specific history and examination. Before total hip arthroplasty, a routine preoperative workup is recommended for high-risk patients: using information from standardised preoperative radiographs while sitting and standing (pelvis, anteroposterior view, lying and standing; spine and pelvis, lateral view, standing and sitting). Important changes can be made during the surgery. If the spine is stiff, attention should be paid to the position of the cup, with increased anteversion, sufficient offset, and larger head that is secure to dislocation - to reduce the risk of dislocation. In the case of a sagittal spinal deformity, the functional coronary pelvic level must be carefully controlled so that it is better to use double mobility cups. Digital systems, such as navigation and robotics, can optimise component positioning although, so far, there is little evidence that the complication rate decreased. Therefore, further studies are warranted.

Synovial Calprotectin for Diagnosing Periprosthetic Joint Infection in Loose Hip and Knee Arthroplasties: A Prospective Cohort Study.

BACKGROUND/AIM: Synovial calprotectin has been demonstrated as a promising biomarker for periprosthetic joint infections (PJI) in painful total hip (THA) and knee arthroplasties (TKA). However, its diagnostic utility has not been evaluated explicitly in cases with marked loosening or migration of the implant. Concerns have already been raised in cases with metallosis and severe periprosthetic osteolysis because wear-induced inflammation may yield false positive results. The purpose of this study was to evaluate calprotectin for the diagnosis of PJI in cases that preoperatively demonstrate moderate to severe periprosthetic osteolysis or implant migration as signs for implant loosening in THA and TKA. PATIENTS AND METHODS: Thirty-three patients were included in this prospective study between February of 2019 and November of 2021. The extent of osteolysis was classified according to Engh et al., Paprosky et al., and the modern Knee Society Radiographic Evaluation and Scoring System. Synovial white blood cell count (WBC), percentage of polymorphonuclear neutrophils (PMC), serum C-reactive protein (CRP) and synovial calprotectin using a lateral-flow-assay were tested against the European Bone and Joint Infection Society (EBJIS) definition for PJI. Statistic quality criteria were calculated and compared using a binary classification test. RESULTS: Ten patients were classified as confirmed infections according to the EBJIS definition (7 THA and 5 TKA). The calprotectin assay yielded a sensitivity of 0.60, a specificity of 0.61, a positive predictive value of 0.40, and a negative predictive value of 0.78. The calprotectin assay resulted in nine false positive and four false negative cases. No correlation between the extent of osteolysis and false classification by means of the calprotectin assay was observed. CONCLUSION: The diagnostic accuracy of synovial calprotectin is impaired if moderate to severe signs of implant loosening are present. If PJI is unlikely, the calprotectin LFT can be applied as a further exclusion tool as the negative predictive value remains relatively high.

Percutaneous mechanical thrombectomy in acute and subacute lower-extremity ischemia: impact of adjunctive, solely nonthrombolytic endovascular procedures.

PURPOSE: We aimed to evaluate the role of adjunctive, solely nonthrombolytic endovascular therapy in treatment of acute lower-extremity ischemia by rotational percutaneous mechanical thrombectomy. METHODS: A retrospective, single-center evaluation of 165 patients (167 limbs) that underwent rotational percutaneous mechanical thrombectomy between 2009 and 2016 was performed. RESULTS: Rotational percutaneous mechanical thrombectomy was used as a single therapy in 9.0% (15 limbs), followed by percutaneous aspiration thrombectomy in 6.0% (10 limbs), percutaneous transluminal angioplasty in 19.8% (33 limbs) and stenting in 25.7% (43 limbs). Rotational percutaneous mechanical thrombectomy was followed by any combination of these three interventions in 39.5%. Clinical and technical success was documented in 92.2%, complications in 10.3% (n=17). No significant difference in clinical and technical success was observed using rotational percutaneous mechanical thrombectomy alone or with additional endovascular therapy. On a long-term basis, the re-ischemia-free survival was nearly twice as high as in previous studies that reported more cases treated by rotational percutaneous mechanical thrombectomy alone. CONCLUSION: To assure a long-lasting primary patency after percutaneous mechanical thrombectomy, concomitant treatment of underlying lesions with adjunctive, nonthrombolytic endovascular methods should be considered.

Diagnostic algorithm in septic total knee arthroplasty failure - What is evidence-based?

Prosthetic joint infection (PJI) is among the most common differential diagnoses of total knee arthroplasty failure. It is a challenging complication, not least because of the difficulty of establishing the correct diagnosis. The fact that no single diagnostic parameter or test has been identified that can accurately rule in or out PJI has led to an evolution of similar but competing definitions of PJI on the grounds of an array of criteria. This development has had very positive effects on the scientific evaluation of various methods of PJI diagnostics and treatment because of an increased comparability. However, it can be challenging to stay abreast of the evidence these definitions are based on. Also, the definitions alone do not necessarily entail an algorithm to aid in evaluating the right criteria in a sound order to be able to use the definitions as a sensible tool. The aim of this overview is to state the most recent evidence on the diagnostic parameters included in the most established PJI definitions and to exhibit and compare the few algorithmic approaches published. Clinical symptoms of PJI are very rarely reported on in the literature, hence the evidence on their diagnostic value is poor. The only symptom that is part of the established PJI definitions is the presence of a fistula. Concerning serological markers, CRP and ESR are still the common denominator in the literature, most recently accompanied by D-Dimer as a potentially suitable marker that has been included in the most recent update of the International Consensus Meeting (ICM) criteria. Imaging plays a minor role in the diagnostic cascade because of inconsistent evidence, and no role whatsoever in the established definitions. The most important preoperative diagnostic measure is arthrocentesis and cultural and cytological analysis of the synovial fluid. The much acclaimed α-Defensin test has so far not been included in the established criteria due to inconsistent reports on its diagnostic accuracy, it is, however, in wide use and considered an optional diagnostic tool for inconclusive cases. The most diagnostic accuracy lies in the cultural and histological analysis of periprosthetic tissue biopsies, whether they are gathered in a small procedure or during arthroplasty revision. Published algorithmic approaches to PJI diagnosis are much rarer than the well-established definitions by various associations. With their PJI definition, the American Academy of Orthopedic Surgeons (AAOS) published a consensus based flowchart for PJI diagnosis. Another algorithm was proposed as part of the endeavor of the MSIS and the first consensus meeting, also based on a consensus among experts. There have been two more recent publications of flowcharts based on the current evidence, one introduced at our institution in 2013, one established in 2020 by the German Society for Arthroplasty (AE).

Does radiopaque cement conceal periprosthetic bone loss around femoral stems?

BACKGROUND: Periprosthetic bone remodelling may increase fracture risk and deplete bone stock around hip implants. These changes are in part caused by implant design, advocating an early evaluation of bone remodelling properties of new implants. This can be done by repeated dual-energy x-ray absorptiometry (DXA) measurements. We know that radiopaque cement falsely elevates bone mineral density (BMD) in single measurements, however, its impact on repeated measurements, i.e. BMD changes is unexplored. We have therefore investigated whether the presence of radiopaque cement affect repeated BMD measurements. METHODS: 33 patients eligible for total hip replacement were randomly assigned to either radiopaque or radiolucent cement. BMD changes up to 12 months were measured by DXA, in addition to Harris Hip Score, plain radiographs and radiostereometric analysis (RSA). RESULTS: Periprosthetic BMD declined during the first 3-6 months in all zones in both groups. The greatest reduction (14%) was seen in the proximal Gruen zones (1 and 7). We found a significant difference in Gruen zones 1 and 2, where the measured bone loss was higher in the radiolucent cement group. CONCLUSIONS: The presence of radiopaque agents in bone cement may influence DXA measurements of bone remodelling.ClinicalTrials.gov identifier NCT00473421.